1 ♖e1x♗e7+! +- wins even though the e7-square has four(!) defenders versus only one(!) attacker, even though the ♖ is more valuable than the ♗, because the e7-square is <LINED UP> with both the Black e8-king and the Black d7-queen and White controls *both* of those <ALIGNMENTS>.

Make forcing moves and other threats that coerce your opponent to line up his pieces, forming <PINNING CHAINS> and <SKEWERING CHAINS>, and then <PIN> and <SKEWER> these enemy pieces that you have forced into alignment.

So if there are _FOUR_ pieces in a row, we need to move one of our pieces out of the way with a <GAIN OF TIME (CLEARANCE)> so that we will have the requisite _THREE_ pieces in a row for the <DISCOVERED ATTACK>.

Your pieces are -NOT- safe if they are in <ALIGNMENTS/CONFIGURATIONS>: files, diagonals, ranks, pawn forks, knight forks, king forks.

Your pieces are <LINED UP>, that is, your pieces are in an <ALIGNMENT>, if an enemy piece can exploit the <SQUARES> on which those pieces reside. And then it's a simple matter of <ACTS - ALIGNMENTS CREATE THREATENED SQUARES>.

In the Greenfeld-Daly Irish Ch. (9) 2008 game, the White c2-rook and White f3-queen -ARE- <LINED UP> via the e4-square because the light-squared Black b7-bishop on that e4-square can exploit the fact that the White rook and queen are on the c2- and f3-squares, respectively.

And in Adams-Bareev Corus 2004, the Black c8-rook and Black g8-king are <LINED UP/MAKE AN ALIGNMENT> because a White bishop on the e6-square can attack both of those Black pieces on the squares on which they reside (c8 and g8) (♖e1xe6! 1-0 <reload>).

Of these <ALIGNMENTS/CONFIGURATIONS> the most dangerous is the <KNIGHT FORK ALIGNMENT> when an enemy knight is located nearby or is centralized. See the games Topalov vs Nisipeanu, 2007 (White d3-queen + White g2-king with Black d5-,e6-knights) and A Aleksandrov vs Adams, 2002 (White h3-queen + h1-king with Black g4-knight) for examples of this particular <ALIGNMENT/CONFIGURATION>.